Cleaning and pickling of metals



' The agents which ma cleaning or pickling bat according tothe' ponds D. Em oram invention relates tothe cleaning and i f pickling-ofmetals, and articularly to the pickling .ofriron or rstee to remove scale 7 therefrom, although the invention is of more .or less general application to the cleanin -or pickling of metals such as iron or stee i for the removal of oxides or scale therefrom. i The pickling or cleaning of iron or steel is commonly effected by means of acid picklin or cleaning baths which remove the :sca e or oxide from the metal. The pickling "-baths commonly "employed are acid baths which often attack the metal-as wellas the scale. This action on the metal is undesira-fg ble and objectionable, involving not only ex cessive consumption of acids, but also corrofsion or dissolving of metal and tending g-tO give a ;r0ugh or pitted surface arm comm; *mconromrnn, or toms-n;

' a in moi mimics I anon/r0 a r.

i *ilnstead it 8: using acid sulfate baths. I

-' The amount of th for carrying outgthe el operation can {be varie i-Infgeneral vp r'c t qi lmfherea e Z a 31 18, 'forflgi mpl V quired, for 'example,- a;small naction of one *The resent invention provides" proved ath for pickling or cleaning metal -;.--?and also an improved process of pickling or cleaning the metal in which the acid pick-fig spling bath has incorporated therein asmall" -amount of inhibiting mercapto ,and particularly a amercapto thiazole. 5 -2 v to (is and, articularly a mergapto tliiazole prevents or retards or inhibits-tlie fitta'cwbf the acid I have found that the addition of a sm amount of suitable ii e P 1 y a pickllng bath on'the metal iwithout'interfer-" 'jther i til Fthe in mg with the removal of scale or oxide by the acid bath.

present invention,'include various .mercapto g it mentioned are used such as are commonly employed iol'i pickhng or cleani iron and steel, sp mming example aout ten percent1ofj sulf uriacid be added to the I:

.s without interfering scale or 'oiide n v .a 18 also als'avm mt e an; as ell asi; y

thej

a are ski n theipr a vmna! f ponroaarron cor-saw am i i p-' time acid bathgother acid baths can hewused including a such apw thiaz le added t ,the bath ssma'll amount'of a suitable compoundJ-is re- 1. A non-oxidizing mineral acid bath for cleaning or pickling metals which comprises a small amount of a mercaptothiazole.

2. A non-oxidizing mineral acid bath for 5 cleaning or pickling metals which comprises a small amount of a mercaptobenzothiazole.

3. A bath for cleaning or pickling metals comprising sulfuric acid and a small amount of a thiazolc.

4. A bath for cleaning or pickling iron or steel comprising sulfuric acid and a small amount of a mercaptothiazole.

5. A bath for pickling or cleaning metals comprising sulfuric acid and a small amount of a mercaptobenzothiazole.

In testimony whereof I affix my signature.

GEORGE D. CHAMBERLAIN. 

